Vitreous substance.



therefore to produce a vitreous substance.

*sTATES "PATE T oriucnl FRANZ woLF-B'tmcxHARn'r, or IBIEBBICH AND'WILHELM, BORCHERS, OF A AC HEN,

GERMANY, ASSIGNOBS' TO ZIBKONGLAS GESELLSGHAFT M. B. H., OF WEISS- FRAUEHHQF, rR NKFonr-ou-rHE-MAIN, GERMANY.

- vrrzanous sunsrimcn.

1 ,086, 1 'R'o Drawing.

s edaeatm'or Letters Patent. a pncauon flledNovember 9,1911. seria 'naesasos.

a tas Feb. 3, 1914.

To all whom it may concern Be it known that we, FRANZ WOLFrBURCK- HARD'IV', chemist, a subject of the King of Prussia, and resident of Biebrich on thee {5 'Rhine, Germany, and WILHELM BOROHIERS,

- chemist, a subject of the King of Prussia.

and resident. of 15 Ludwigsallee, city of Aachen, Germany, have jointly invented a new and useful Im, roved' Vitreous Substance, of which the ollowing'isa speclfication. j I

This invention relates to the production of a new or improved vitreous substance of the nature of quartz glass but of greater strength and less liable to devitrification and deformation when'subjected to heat.

' Quartz glass, as is well known, is obtained by melting pure natural quartz or silica free from water, which gives a'vitreous sub stance having all the outward properties of glass but being difierent therefrom in its chemical composition,- being. a substance of pure'acid character possessing great durability against chemical and thermal influ-.

ences'. Quartz glass, however, when subjected to high temperatures, tends to devitrify, that is to say, it transforms from the amorphous state into a crystalline state, in which condition it considerably diminishes in strength and may be crushed between the fingers. Moreover, when quartz is gradually heated to fusing point, it is found that it begins to soften at a temperature of about 17 00 centigrade, which is somewhat below that of its '35 fusing point... As soon as the softening point p is reached, the quartz glass rapidly deforms 1 the t is to say, rapidly loses 1ts shape, an for these reasons quartz glass hasbeen found deficient for many practical purposes. v

Theobject of the present mvention' [is i which, while possessing all the -good qualities OfKfgaItZ glass, will'be of greater s t a eing less liable 'to'devitrification and deformatiomthus enablin articles to be manufacturedtherefrom' Whi shall be excellently durable against thermal influences.

, Accordin to the'present invention, small quantities 0 "one or more of the acidic oxids of the fourthgrou of the periodic system are incorporated Witihthe-quartz glass during its manufacture. These acidic oxids are Mvery durable againstchemical andthermal 1' influences, but, of. these oxids, thetitanic proximates that of silica. in the molten silica or form silicates therev its capabilit fomation and its capability of withstanding and zirconium oxids are most suitable because of their high melting oint and be-' cause their resistance to aci s closely ap- The oxids dissolve with which dissolve in the excess molten s1l 1ca and, owing to their high melting points, the fusing point of the mixture will vary but little and may even exceed that. of pure quartz glass. It. has been found preferable not to add more than Qper cent. of theseoxids and that when the oxids are added to the silicain from fractions of o' e per cent. to about 5 per cent., the liabili y of theproduct to devitrify is considerably less than that of pure quartz glass while, at the same'time, the softening point is slightly hlgher than that of quartz glass and that when this softening point is reached, the product does not deform as rapidly as does pure quartz glass. The product is also capable of withstanding greater breaking strains and is also of greater durability against chemical influences than pure quartz glass.

It will be understood that either titanic oxid or'ziconium oxid or both may be mixed with the silica prior to fusion.

The mixture of-the silica and oxids may be fused in an electric furnace or by means of an oxy-hydrogen or oxy-coal. gas flame or the like. The vitreous substance thus obtained may be worked and treated in the ordinary manner.

We claim 1. As anew com osition of matter, a vitreous substance of the nature of quartz glass and derived from silica and a small quantity, not exceding 5 per cent. ofan acidic oxid of the fourth group of the periodic system, characterized by its durability of withstandingv .breaking strains and c" emical influences.

2. As a new com osition of matter, a vit-; reous substance 0 the nature of quartz glass and derived fromsilica and a small quantity, not exceeding5 per cent, of a plurality of'acidic oxids of the fourth; group of the periodic system, characterized by its durability against devitrification and dea'gainst devitrification and deformation and 105 breaking strains and chemical influences.

3. As a new com osition of matter, a vitreous substance 0 the nature of quartz glass and derived from silica and a small its durability against devitrification and defquantity, not exceeding 5 per cent, of zirormation and its capability of withstanding conium oxid, characterized by its durability breaking strains and chemical influences.

against-devitrification and deformation and In witness whereof we have hereunto set 15 5 its capability of withstanding breaking our hands in the presence of two witnesses.

strains and chemical influences. FRANZ WOLEBURCKHAfiDT.

4. As a new com osition of matter a vitreous substance 0 the nature, of quartz WILHELM BORCHERS' glass and derived from? silica and a small Witnesses: 4 I 10 quantity, not exceedmg 5 per cent, of titanic J AKOB KANSSEN,

oxid and zirconium oxid, characterized by HENRY QUADFLIEG. 

